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Research: Grizzlies not so dependent on pine nuts
Dec 11, 2013 - By Matthew Brown, The Associated Press
Grizzly bears in the greater Yellowstone ecosystem have a varied diet and are minimally affected by the decline in the number of whitebark pine trees, federal research found.
The findings were presented in Bozeman at a meeting of the Yellowstone Ecosystem Subcommittee of the Interagency Grizzly Bear Committee. The subcommittee voted 10-4 to accept the research findings. It also gave preliminary approval to a motion that recommends the U.S. Fish and Wildlife Service remove federal protections for the bears, currently listed as "threatened."
The USFWS delisted the bears in 2007, but a federal judge returned the protection two years later, saying the effect of the decline in whitebark pine trees on bears wasn't given adequate consideration. Whitebark pine nuts are a key food source for grizzlies as they prepare for hibernation.
Research found that grizzly bears eat more than 200 types of food, 75 of them frequently. That means when one food source is low, as the whitebark pine is, they find another, said Frank van Manen, interagency study team leader.
The studies found grizzlies in the Yellowstone ecosystem have been eating more elk and bison meat as the availability of whitebark pine nuts declined. Other studies found that grizzlies' body weight and fat levels have remained unchanged, regardless of production of whitebark pine cones.
The studies also found that the number of grizzly bears in the ecosystem is growing more slowly than it has in the past, in part because there are more of them sharing the same landscape and resources.
The interagency study team estimates there are 741 grizzly bears in the ecosystem.
Van Manen hasn't completed an eighth study looking at whether bears were more likely to die if they had to change from pine seeds to another kind of food.
Representatives from the Montana Department of Fish, Wildlife and Parks, the Wyoming Bureau of Land Management and Yellowstone and Teton national parks voted against the motion, saying they wanted to confer with staff and wait for some final results due out at the end of the month.